Do you ever wonder what it would be like to have the knowledge that you have today, but at a younger age? Being older and wiser, then going back to an earlier time, would remove a lot of stress from life. The formative years of middle school, high school and even college would have fewer bumps in the road—and fewer major mistakes. What about in the business world? What do you know about business now that you wish you’d known then?

Here are my top five:

Your college major becomes less important with age. What to study in college becomes an agonizing decision for many high school and college students. But is it really all that important? I know now that instead of learning about one single subject, learning how to learn is far more important. I also learned that a well-rounded education is more important than my field of undergraduate study. Even beyond the undergraduate level, I know that my graduate general business education has benefited me much more than my undergraduate major (although a technical undergraduate degree combined with a graduate business degree seems to be a solid formula for business success).

You are choosing a career in an industry with your first job out of college. I wish I had known how important my first job out of college was. Your first job can get you started on a career path. No matter what it is, it makes you part of an industry. And in a tight labor market, crossing over industries to another job becomes much more difficult. Choose an industry with the best career path out of college, even if it’s not necessarily the best job offer.

The importance of sales and selling. Successful or unsuccessful selling will impact your business more than other functional business disciplines over time. In business education, we understate the importance of selling, perhaps because it is more difficult to teach than accounting, operations or marketing. I wish that I had understood just how important sales are to any business, particularly small businesses. I would have respected and developed my selling skills sooner.

Nothing replaces business experience. We cannot replicate real-world business learning in a classroom environment. And failure is a very important part of business experience. I know now that I have learned more from my failures than I have from my successes. The point is not just to fail, but to fail quickly, learn from it and move on. I wish I had known that business schools cannot teach some of the most important lessons about small business and will never replace street credibility or learning from failure.

Business is emotional. I wish I knew that business decisions are based more on human emotions than on data-oriented problem-solving. Educational institutions teach us how to manage data, but not how to manage people. Most of business is about the management of interpersonal relationships, and I’ve learned that personal relationships and human emotions, particularly egos, trump quantitative problem-solving.

To write this article, I had to look back in time to when I was 18. I needed to remember what was important to me then and what misconceptions about business I might have held. With all this in mind, I wonder if what I know now would have made my business journey back then less enjoyable, even if it would have made it easier.

Tell us what you know now that you wish you’d known then in the comments section below.